GENERA OF FAVOSITID^. 185 



the fact that Cohtmnaria Goldfiissi is beUeved to belong to the 

 Hudson River formation, would seem to point to the at least 

 specific distinctness of the present coral. If a further examina- 

 tion of C. Goldftissi, Bill., should show it to be possessed of 

 mural pores, then it also must be removed to the genus Nydo- 

 p07'a. Lastly, there is a close general resemblance between 

 the present form and Cohtmnaria (?) Halli, mihi (the Colum- 

 naria alveolata of American writers), and it is not at all impos- 

 sible that the latter may be shown to have perforate walls, and 

 thus to truly belong to the present genus. 



Formation and Locality. — Not uncommon in the Trenton 

 Limestone of Peterboro', Ontario. 



Gemis BiLLiNGSiA, De Koninck, 1876. 

 (Rech. sur les Foss. Pal. de la Nouv. Galles du Sud., p. 75, PL II., fig. 4.) 



Ge7t. Char. — " Corallum composed of compressed corallites, 

 united by their walls, and communicating freely with one 

 another by means of lateral openings. Calices small, ovate, 

 and furnished with a few septal striae. Tabula apparently 

 absent." 



Obs. — This genus was founded by Professor De Koninck 

 (loc. cit.) for a single species of coral [B. alveolaris), from strata 

 of Devonian age, near Zass, on the Murrumbidgee River, in 

 Australia. Not having seen any examples of the form in 

 question, I can simply reproduce the above generic diagnosis 

 and one of the figures (PL IX., fig. 4) given by De Koninck. 

 Assuming the correctness of the description given — as to which 

 the great experience of this distinguished observer leaves little 

 room to doubt — we have to deal in Billingsia with a perforate 

 coral, belonging to the Favositidcs, but distinguished from the 

 other members of this family by the suppression of the tabulse. 

 The mural pores are apparently numerous and of large size, 

 but they do not seem to have any serial arrangement. Profes- 

 sor De Koninck expresses the opinion that the genus is in- 



